In recent years, the optical image measuring technology of forming an image showing the surface and internal morphology of a measurement object by using a light beam from a laser light source or the like has received attention. Since this optical image measuring technology does not have invasiveness against a human body unlike the X-ray CT, it is expected that application of this technique is developed especially in the medical field.
Patent Document 1 discloses an optical image measurement device having a configuration that: a measuring arm scans an object by a rotary conversion mirror (Galvano mirror); a reference arm is provided with a reference mirror; at the outlet, an interferometer in which the intensity of light appearing by interference of light fluxes from the measurement arm and the reference arm is analyzed by a spectrometer is used; and the reference arm is provided with a device that gradually changes the light flux phase of a reference light by discontinuous values.
The optical image measurement device disclosed in Patent Document 1 uses a method of so-called “Fourier Domain OCT (Optical Coherence Tomography).” In this method, by applying a low-coherence light beam to a measurement object, acquiring the spectrum intensity distribution of the reflected light, and executing Fourier transformation on the spectrum intensity distribution, the morphology in the depth direction (z-direction) of the measurement object is imaged.
Further, the optical image measurement device disclosed in Patent Document 1 is provided with a Galvano mirror for scanning with a light beam (signal light) and is thereby capable of forming an image of a desired measurement target region of a measurement object. Since this optical image measurement device scans with a light beam in only one direction (x-direction) orthogonal to the z-direction, a formed image is a two-dimensional tomographic image in the depth direction (z-direction) along a scanning direction (x-direction) of the light beam.
Patent Document 2 discloses a technology of forming a plurality of two-dimensional tomographic images in the horizontal direction by scanning with a signal light in the horizontal and vertical directions to acquire and image three-dimensional tomographic information of a measurement range based on the plurality of tomographic images. This three-dimensional imaging is executed by, for example, a method of arranging a plurality of tomographic images in the vertical direction and displaying the tomographic images (referred to as “stack data” or the like), or a method of executing a rendering process on a plurality of tomographic images and forming a three-dimensional image.
Patent Document 3 discloses a configuration in which the optical image measurement device as described above is applied in the ophthalmic field.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 11-325849
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2002-139421
[Patent Document 3] Japanese Unexamined Patent Application Publication No. 2003-543